The present exemplary embodiment relates to a cleaning system and, more particularly, to a device for use in a fuser apparatus of an electrophotographic marking device for cleaning the fuser roll of toner particles.
In typical electrophotographic image forming devices, such as copy machines and laser beam printers, a photoconductive insulating member is charged to a uniform potential and thereafter exposed to a light image of an original document to be reproduced. The exposure discharges the photoconductive insulating surface in exposed or background areas and creates an electrostatic latent image on the member, which corresponds to the image areas contained within the document. Subsequently, the electrostatic latent image on the photoconductive insulating surface is made visible by developing the image with a marking material. Generally, the marking material comprises pigmented toner particles adhering triboelectrically to carrier granules, which is often referred to simply as toner. The developed image is subsequently transferred to the print medium, such as a sheet of paper. The fusing of the toner image onto paper is generally accomplished by applying heat and pressure. A typical fuser apparatus includes a fuser roll and a pressure roll which define a nip therebetween. The side of the paper having the toner image typically faces the fuser roll, which is often supplied with a heat source, such as a resistance heater, at the core thereof. The combination of heat from the fuser roll and pressure between the fuser roll and the pressure roll fuses the toner image to the paper, and once the fused toner cools, the image is permanently fixed to the paper.
Some toners adhere well to paper but do not adhere well to themselves. Included among these are toners where the particles are small in dimension, relative to the size of the nip. As a result, they may not receive sufficient compressive force to sinter well. This can lead to adherence of significant quantities of unsintered toner particles to the fuser roll. Some toners are more prone to fuser roll contamination than others. The extra toner tends to accumulate on the stripper fingers, which serve to release the fused image from the fuser roll, and on the temperature sensors. From here, the toner can be retransferred to the paper in the form of small clumps that create visible image quality defects.
Fuser assemblies typically include a cleaning system by which the fuser roll can be automatically cleaned and/or supplied with a lubricant or release agent. In some cleaning devices, a cloth web is urged against the surface of the fuser roll at a location generally away from the nip formed by the pressure and fuser rolls. Other systems include a rotating oil-filed roller with a layer of permeable material, which slowly releases the oil on to the fuser roll and absorbs excess toner therefrom. In some cases, the toner can build up on the cleaning system and be retransferred as clumps to the fuser roll, to be deposited on a subsequent sheet. This can cause visible defects in the printed copies. Spots and strings of toner can also be deposited on the stripper fingers and temperature sensors of the fuser apparatus. The toner can also be transferred to the pressure roll, particularly after a pause in printing when rotation of the pressure and fuser rolls is recommenced. The toner is transferred from the pressure roll to the back side of the first copy and leads a user to request a servicing of the printer.